1. Field of the Invention
The present invention relates to a closing structure of a fluid-dispensing container suitable for an aseptic eyedropper, cosmetic liquid container without antibiotic, or the like. Herein, xe2x80x9cfluidxe2x80x9d means material capable of flowing, such as fluid or fluidized material, including liquid, paste, powder, and the like.
2. Description of Related Art
Closing structure of a fluid-dispensing container including a dispensing valve secured in the mouth of one of various types of containers, which remains closed if the pressure in the container is atmospheric and opens if the pressure exceeds a predetermined pressure, is disclosed in each of Japanese Laid-open Patent Application No. Hei. 8-282704, Japanese Laid-open Patent Application No. Hei. 8-282703, U.S. Pat. Nos. 5,213,236, 5,339,995, and 5,439,143.
The above-mentioned closing structure is preferably usable in dispensers of eyedrops, i.e. ophthalmic liquid medicament, liquid detergents and liquid foods. A container having such closing structure surely prevents leakage of contained liquid and discharges the liquid smoothly as needed.
With the above-described prior art closing structure, a negative pressure is generated within the container after ceasing the discharge of the contained liquid. The negative pressure makes the dispensing valve to open inward, thus introducing ambient air into the container until the negative pressure disappears. As the ambient air includes pathogenic microbes such as true fungi, bacteria, protozoa and viruses, the microbes are mixed in the liquid in the container. Therefore, to subdue such microbes, several kinds of preservatives, antibiotics, antibacterial agents, antiseptics or antimicrobials, hereinafter named generically as xe2x80x9cpreservativesxe2x80x9d, to meet purposes of the contained liquid are added to the liquid.
However, various problems resulting from side effects of the preservatives have been pointed out recently. For example, repetitive use of eyedrops containing preservatives might cause inflammation or damage of eyes. Especially for those wearing contact lenses, use of eyedrops containing preservatives even in low density might cause allergic reaction. Some preservatives contained in shampoo are pointed out to have possibility of causing inflammation of scalp or falling off of hair. Furthermore, consumers of recent years tend to dislike and avoid contained preservatives themselves.
Japanese Laid-open Patent Application No. Hei. 4-297264 and Japanese Laid-open Patent Application No. Hei. 6-14972, for example, disclose eyedrops containers with filters secured in a discharging passage for eliminating only additives such as preservatives that make no contribution to the medicinal virtues when liquid contained in the bottle is discharged dropwise through the discharging passage. However, such prior art containers cannot fully lower the density of preservatives if the eyedrops contain enough amount of preservatives to achieve sufficient sterilization effect. More specifically, because microbes in the ambient air are allowed to come to be mixed in the liquid within the above-described eyedrops container and the microbes mixed in the liquid are sterilized with the preservatives, it is impossible to fully lower the density of preservatives in the liquid, therefore, some amount of preservatives remains in the eyedrops to be discharged dropwise.
Japanese Laid-open Utility Model Application No. Sho. 63-184037 discloses an eyedrops container, whose body has a tubular shape whose end portion is of compressed shape or whose body is foldable so that it can be transformed into compressed shape, enabling volume within the container body to decrease with decrease of liquid contained therein. The container has a hydrophilic filter secured in the discharging passage to discharge liquid dropwise. The filter allows the ophthalmic liquid medicament to pass through and does not allow air and bacteria to pass through. Such prior art eyedrops container can lower density of the preservatives in the liquid as low as possible because it prevents microbes from mixing into the contained liquid by completely preventing ambient air from entering the container. However, the eyedrops container cannot have transparency because the body of the container cannot be made of plastic material but should be made of aluminum tube and the like, as plastic deformation of the container body of monolayer structure is required. Therefore, remaining amount of the eyedrops cannot be seen from outside. Furthermore, it cannot be kept upright since the container body is deformed compressedly as the contained liquid is consumed, thus spoiling convenience in use.
Each of Japanese Laid-open Patent Application No. Hei. 9-175566 and Japanese Laid-open Patent Application No. Hei. 10-165222 discloses a dispensing container comprising a delaminatable laminated bottle and a closing member such as a cap or a plug mounted to and closing the mouth of the bottle. The laminated bottle consists of an outer layer and an inner layer laminated onto and delaminatable from the inner surface of the outer layer. The outer layer forms an outer bottle, whereas the inner layer forms a bag for containing fluid. The outer layer has a vent to introduce ambient air into the space between the inner and outer layers. The closing member has therein a discharging passage through which liquid is discharged out of the inner layer. A check valve is secured in the discharging passage. This type of dispensing container introduces ambient air into the space between the outer and inner layers as the liquid contained in the bag decreases, deflating the bag, and prevents flowback of the liquid and entrance of ambient air into the bag by means of the check valve. Therefore, the liquid in the bag is protected from contamination by microbes, obviating the need of adding preservatives into the liquid, for the liquid is discharged without entrance of ambient air into the bag. However, liquid remaining in the discharge opening on the downstream side of the check valve may be contaminated by microbes such as true fungi, bacteria and viruses as the liquid is exposed to the ambient air, thus incurring possibility of dispensing contaminated liquid.
The invention aims to provide a closing structure of a dispensing container which has a valve which is closed if pressure acted on the inner surface of the container is atmospheric and opens if the pressure acted on the inner surface exceeds a predetermined pressure and which clears away the difficulties of the prior art structure.
A closing structure of a dispensing container according to the first aspect of the present invention provides a closing member mounted on the mouth of a bottle including a body and a mouth, the closing member having a discharging passage through which fluid is discharged out of the bottle; a dispensing valve is located in the passage in order to open and close the passage; and a filter is located in the passage on the downstream side of the valve. The downstream end portion of the passage may be defined on the downstream side of the filter. The valve may include a valve flange, a valve head and a connector sleeve of a resilient flexible structure. The valve flange seals a periphery of the passage. The valve head may have an orifice that opens to allow flow of fluid therethrough if a first predetermined pressure acts on the inner surface of the valve head and closes to stop the flow of fluid if the first pressure removes from the inner surface. The connector sleeve may be connected to an inner periphery of the valve flange at one end and to an outer periphery of the valve head at the other end. The connector sleeve may be deformed to shift the valve head downstream if a second predetermined pressure which is less than the first pressure acts on the inner surface of the valve head, further the sleeve may return to its original shape if the second pressure removes from the inner surface to suck fluid remaining within the downstream end portion of the passage back to the upstream side of the filter.
The dispensing container may be formed as a bottle with monolayer structure. Otherwise, the container may also include an outer bottle including a body and a mouth and an inner bag for containing fluid housed within the outer bottle, the inner bag deflating or collapsing with the decrease of fluid contained in the bag.
Even if internal pressure of the container should rise in smaller amount than a predetermined amount, the rise of the internal pressure is modified and the orifice of the dispensing valve is kept closed, because the valve head is shifted downstream owing to the closing structure according to the first aspect described above, preventing undesired outflow of fluid in storing or handling. The contamination of fluid from external cause is prevented because fluid remaining in the downstream end portion of the passage, which is on the downstream side of the filter, is sucked back to the upstream side of the filter through the restoring force of the valve. The filter should preferably be one that is able to prevent predetermined kinds of microbes such as bacteria and true fungi from passing through from the downstream side (i.e., outside of the container) to the upstream side (i.e., inside of the container). For example, a membrane filter is preferred.
A closing structure according to the second aspect of the present invention is suitable for a dispensing container having an outer bottle including a body and a mouth and an inner bag for containing fluid housed within the outer bottle and having a discharge opening communicating to the mouth of the outer bottle, the outer bottle having a vent to introduce ambient air into space between the outer bottle and the bag. The closing structure provides a closing member having a discharging passage through which fluid is discharged out of the bag and mounted on the mouth of the outer bottle and a dispensing valve located in the passage in order to open and close the passage. The valve may include a valve flange and a valve head. More specifically, a valve flange and a valve head are connected via a connector sleeve of a resilient flexible structure to constitute the valve. The valve flange seals a periphery of the passage. The valve head has an orifice that opens to allow flow of fluid therethrough if a first predetermined pressure acts in the bag and closes to stop the flow of fluid if the first pressure removes. The closing member may have a supporter that makes contact with and supports the valve head to prevent the orifice from opening if a negative pressure is generated in the bag.
Owing to this aspect, the fluid in the container is effectively protected against the attack of microbes in the ambient air because of liquid-tightness and air-tightness when the orifice of the valve is closed, because the orifice is defined by the valve head itself. The valve head is made of elastic material such as rubber to be deformable so that it is able to open and close the orifice. The container is constituted by the outer bottle and the inner bag, which generates a negative pressure in the inner bag after dispensing fluid. The supporter prevents the valve head from opening the orifice through inward deformation by the negative pressure, thus preventing ambient air and the liquid that is once discharged through the valve from entering through the valve and into the bag, obviating the need of preservatives in the liquid in the bag.
Most preferably, the closing structure according to the invention provides all components included in the first and second aspects.